A US salvage boat impounded by Spanish authorities in a dispute over sunken treasure has been allowed to leave the port of Algeciras in Spain.

The Odyssey Explorer was seized by Spanish police on Tuesday, and taken to Algeciras, where the captain was subsequently arrested for a short time.

The dispute follows the discovery in May of shipwreck booty estimated to be worth $500m (£245m).

The Spanish government asserts it may have a claim on the treasure.

But the US salvage company, Odyssey Marine Exploration says the trove - said to include half a million silver coins and hundreds of gold objects - was found in international waters.

Stand-off

The Odyssey Explorer was cleared by a Spanish judge and harbour authorities to leave Algeciras port on Saturday, said Odyssey Marine Exploration in a statement.

It said the ship would travel to another port, from which search and recovery operations would recommence.

There was a tense stand-off earlier in the week, after the boat left the port of Gibraltar, a British territory. The Spanish Navy threatened to open fire if civil guards were not allowed on board to carry out a search.

The boat was then impounded in Algeciras, where its captain Sterling Vorus was arrested.

Mr Vorus was freed on condition he present himself every fortnight to the judicial authorities.

Madrid suspects the 17th Century sunken treasure galleon may either have been Spanish or have gone down in Spanish waters.

The American firm will only reveal the wreck - codenamed Black Swan - is somewhere in the Atlantic and says it is keeping the location secret to deter looters.

Odyssey said it flew all of the 17-tonne treasure haul from Gibraltar back to Florida in May.

In July Spanish police searched another ship belonging to Odyssey, the Ocean Alert, after it left Gibraltar.